The present invention is directed generally to vehicle-mounted implements and more particularly to a novel arrangement for effecting attachment of a snowplow blade or the like to a vehicle.
Many arrangements have heretofore been proposed for attaching an implement such as a snowplow blade or the like to a vehicle for use in performing snow removal or other similar tasks. Effective plowing requires that the blade be capable both of angular movement both left and right and of vertical movement, raising and lowering the blade to assume a transport position and a working position, respectively. Additionally, when the snowplow blade is in the working position, it is desirable that the effective weight of the blade be relatively low and that the blade be allowed to "float" relatively freely in order to substantially follow the contour of the surface to be plowed.
To these ends, a relatively effective hydraulic system has been heretofore developed, including a pair of opposed cylinders for effecting left and right angling movement and a generally vertically disposed cylinder for effecting raising and lowering of the snowplow blade. Moreover, there has been developed an effective dual-frame system for carrying the snowplow blade upon a vehicle. This system includes a first framework for mounting the blade together with the hydraulic cylinders for left and right angling thereof and a second framework or lift frame mounted to the vehicle, for receiving the blade-carrying frame and for carrying the raising and lowering hydraulic apparatus.
However, one problem still encountered is that of providing effective, yet simple, coupling or joining structure for attaching the blade-carrying frame to the vehicle mounted frame. In particular, many such coupling or joining arrangements have been relatively complex, utilizing a great number of parts and requiring considerable skill of an operator in effecting the coupling of the two framework members. Such a coupling must be quite secure and reliable once the two frames are joined for plowing, yet allow some degree of play or movement therebetween. In this latter regard, it is desirable to allow for some degree of twisting or rotation in the horizontal plane of the snowplow blade, in order to more closely follow an uneven ground surface. However, many prior art coupling arrangements have been quite rigid in order to accomplish the desired secure coupling, failing to yield sufficiently to permit such twisting or rotational movement of the blade to a sufficient extent to permit the blade to follow an uneven ground contour in this fashion.